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ARS Home » Midwest Area » West Lafayette, Indiana » Crop Production and Pest Control Research » Research » Publications at this Location » Publication #123639


item Abbasi, Mehrdad
item Goodwin, Stephen - Steve
item Hedjaroude, G

Submitted to: Mycological Symposium Asian Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/17/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: To evaluate the phylogenetic relationships within the Puccinia graminis complex, 20 herbarium specimens of this rust from Iran, USA and Germany, were assessed for internal transcribed spacer (ITS) sequence polymorphisms. Sequences from the ITS1, 5.8S and ITS2 region were subsequently determined for all specimens. Results of the neighbor- joining analysis produced three clades. The first clade consisted of P. graminis isolates on wheat and different grasses solely from Iran and the second clade contained P. graminis isolates on wheat from the USA, on Secale cereale from Germany and on Elymus and Eremopyrum species from Iran. Specimen no.105 on Avena sp. from Iran formed the third clade by itself. In the second analysis, sequences of P. graminis from six formae speciales were downloaded from GenBank and added to the database. The published sequences for the ITS region of P. graminis only include the last 42 bases at the 3' end of ITS1. We therefore used only the alignable data common to all specimens for drawing the tree (i.e., the last 42 bp of ITS1, and all of the 5.8S and ITS2 sequences). In the second phylogram the same three main groups were clearly distinguishable with high bootstrap support. While the ITS sequence data did not support the taxonomy of P. graminis on the basis of urediniospore morphology, DNA sequence variation detected within this region among specimens of P. graminis indicates a high level of variation between specimens in Iran. This suggests the theory of a species complex or one highly variable species for this rust in Iran. This high level of DNA sequence variation also supports the theory that ancestral P. graminis developed in Iran and that this area is one of the primary gene centers of the stem rust pathogen